U.S. patent application number 14/221327 was filed with the patent office on 2015-09-24 for processes for removing polysulfanes and elemental sulfur from hydrogen sulfide.
This patent application is currently assigned to Chevron Phillips Chemical Company LP. The applicant listed for this patent is Chevron Phillips Chemical Company LP. Invention is credited to Maruti Bhandarkar, Daniel M. Hasenberg, Ronald D. Knudsen, Michael S. Matson, Mitchell D. Refvik.
Application Number | 20150266734 14/221327 |
Document ID | / |
Family ID | 53002799 |
Filed Date | 2015-09-24 |
United States Patent
Application |
20150266734 |
Kind Code |
A1 |
Hasenberg; Daniel M. ; et
al. |
September 24, 2015 |
Processes for Removing Polysulfanes and Elemental Sulfur from
Hydrogen Sulfide
Abstract
Disclosed are processes for purifying feed streams containing
hydrogen sulfide and sulfur-containing impurities by removing
sulfur-containing impurities, such as elemental sulfur and
polysulfanes, using solid catalytic sorbents. Also disclosed are
processes for producing hydrogen sulfide.
Inventors: |
Hasenberg; Daniel M.;
(Kingwood, TX) ; Refvik; Mitchell D.;
(Bartlesville, OK) ; Matson; Michael S.;
(Bartlesville, OK) ; Bhandarkar; Maruti;
(Kingwood, TX) ; Knudsen; Ronald D.;
(Bartlesville, OK) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Chevron Phillips Chemical Company LP |
The Woodlands |
TX |
US |
|
|
Assignee: |
Chevron Phillips Chemical Company
LP
The Woodlands
TX
|
Family ID: |
53002799 |
Appl. No.: |
14/221327 |
Filed: |
March 21, 2014 |
Current U.S.
Class: |
423/564 |
Current CPC
Class: |
C01B 17/162 20130101;
B01D 53/485 20130101; C01B 17/168 20130101; B01D 53/8606 20130101;
B01D 2257/308 20130101 |
International
Class: |
C01B 17/16 20060101
C01B017/16 |
Claims
1. A process to purify a feed stream comprising hydrogen sulfide
and sulfur-containing impurities, the process comprising:
contacting the feed stream with a solid catalytic sorbent to remove
at least a portion of the sulfur-containing impurities from the
feed stream to form a purified H.sub.2S stream; wherein the solid
catalytic sorbent comprises a clay; an alkali metal hydroxide or
alkaline earth metal hydroxide impregnated activated carbon; an
alkali metal hydroxide or alkaline earth metal hydroxide
impregnated alumina; an alkali metal hydroxide or alkaline earth
metal hydroxide impregnated alumina combined with a clay; an alkali
metal hydroxide or alkaline earth metal hydroxide impregnated
alumina combined with an activated carbon; or any combination
thereof.
2. The process of claim 1, wherein the solid catalytic sorbent
comprises the clay.
3. The process of claim 1, wherein the solid catalytic sorbent
comprises the alkali metal hydroxide or alkaline earth metal
hydroxide impregnated activated carbon.
4. The process of claim 1, wherein the solid catalytic sorbent
comprises the alkali metal hydroxide or alkaline earth metal
hydroxide impregnated alumina.
5. The process of claim 1, wherein the solid catalytic sorbent
comprises the alkali metal hydroxide or alkaline earth metal
hydroxide impregnated alumina combined with the clay.
6. The process of claim 1, wherein the solid catalytic sorbent
comprises the alkali metal hydroxide or alkaline earth metal
hydroxide impregnated alumina combined with the activated
carbon.
7. The process of claim 1, wherein the solid catalytic sorbent
comprises Calgon.RTM. Carbon ST1-X, Selexsorb.RTM. COS, or a
combination thereof.
8. The process of claim 1, wherein the feed stream contacts a fixed
bed of the solid catalytic sorbent, and the fixed bed of the solid
catalytic sorbent comprises a combination of solid catalytic
sorbents in a mixed bed and/or sequential beds.
9. The process of claim 1, wherein the feed stream and the solid
catalytic sorbent are contacted at a temperature in a range from
15.degree. C. to 35.degree. C., a pressure in a range from 34 kPa
(5 psia) to 1.3 MPa (200 psia), and a WHSV in a range from 0.4 to
2.5.
10. The process of claim 9, wherein for a time period of at least
24 hours, a minimum of 50 wt. % of the sulfur-containing impurities
are removed from the feed stream to form the purified H.sub.2S
stream.
11. The process of claim 1, wherein the feed stream comprises at
least 90 wt. %, H.sub.2S and from 10 to 500 ppm by weight of
sulfur-containing impurities.
12. The process of claim 1, wherein at least 60 wt. % of the
sulfur-containing impurities are removed from the feed stream to
form the purified H.sub.2S stream.
13. A process to purify a feed stream comprising hydrogen sulfide
and sulfur-containing impurities, the process comprising: (i)
contacting the feed stream with a drying agent to remove at least a
portion of moisture (H.sub.2O) from the feed stream; and (ii)
contacting the moisture (H.sub.2O) reduced feed stream with a solid
catalytic sorbent to remove at least a portion of the
sulfur-containing impurities from the feed stream to form a
purified H.sub.2S stream; wherein the solid catalytic sorbent
comprises a clay; an alkali metal hydroxide or alkaline earth metal
hydroxide impregnated activated carbon; an alkali metal hydroxide
or alkaline earth metal hydroxide impregnated alumina; an alkali
metal hydroxide or alkaline earth metal hydroxide impregnated
alumina combined with a clay; an alkali metal hydroxide or alkaline
earth metal hydroxide impregnated alumina combined with an
activated carbon; or any combination thereof.
14. The process of claim 13, wherein the drying agent comprises
calcium chloride, calcium sulfate, magnesium sulfate, alumina,
silica, a molecular sieve, or any combination thereof.
15. The process of claim 13, wherein the feed stream, after
contacting the drying agent, comprises less than 50 ppm by weight
of H.sub.2O.
16. The process of claim 15, wherein at least 60 wt. % of the
sulfur-containing impurities are removed from the feed stream to
form the purified H.sub.2S stream.
17. The process of claim 13, wherein the solid catalytic sorbent
comprises the clay.
18. The process of claim 13, wherein the solid catalytic sorbent
comprises the alkali metal hydroxide or alkaline earth metal
hydroxide impregnated activated carbon, the alkali metal hydroxide
or alkaline earth metal hydroxide impregnated alumina, or a
combination thereof.
19. The process of claim 13, wherein the solid catalytic sorbent
comprises the alkali metal hydroxide or alkaline earth metal
hydroxide impregnated alumina combined with the clay, or the alkali
metal hydroxide or alkaline earth metal hydroxide impregnated
alumina combined with the activated carbon.
20. A hydrogen sulfide production process comprising: (a)
contacting hydrogen and sulfur under conditions sufficient to
produce a feed stream comprising hydrogen sulfide and
sulfur-containing impurities; and (b) contacting the feed stream
with a solid catalytic sorbent to remove at least a portion of the
sulfur-containing impurities from the feed stream to form a
purified H.sub.2S stream; wherein the solid catalytic sorbent
comprises a clay; an alkali metal hydroxide or alkaline earth metal
hydroxide impregnated activated carbon; an alkali metal hydroxide
or alkaline earth metal hydroxide impregnated alumina; an alkali
metal hydroxide or alkaline earth metal hydroxide impregnated
alumina combined with a clay; an alkali metal hydroxide or alkaline
earth metal hydroxide impregnated alumina combined with an
activated carbon; or any combination thereof.
21. The process of claim 20, wherein the process further comprises
a step of contacting the feed stream with a drying agent to remove
at least a portion of moisture (H.sub.2O) from the feed stream
prior to contacting the feed stream with the solid catalytic
sorbent.
22. The process of claim 21, wherein the feed stream comprises at
least 80 wt. % H.sub.2S, and at least 60 wt. % of the
sulfur-containing impurities are removed from the feed stream to
form the purified H.sub.2S stream.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates generally to processes for
purifying H.sub.2S feed streams, and to the removal of
sulfur-containing impurities, such as elemental sulfur and
polysulfanes.
SUMMARY OF THE INVENTION
[0002] This summary is provided to introduce a selection of
concepts in a simplified form that are further described herein.
This summary is not intended to identify required or essential
features of the claimed subject matter. Nor is this summary
intended to be used to limit the scope of the claimed subject
matter.
[0003] Processes for purifying feed streams containing hydrogen
sulfide (H.sub.2S) and sulfur-containing impurities (e.g.,
elemental sulfur, polysulfanes) are disclosed herein. In accordance
with an embodiment of the present invention, one such process can
comprise contacting the feed stream with a solid catalytic sorbent
to remove at least a portion of the sulfur-containing impurities
from the feed stream to form a purified H.sub.2S stream. The solid
catalytic sorbent can comprise a clay, an alkali metal hydroxide or
alkaline earth metal hydroxide impregnated activated carbon, an
alkali metal hydroxide or alkaline earth metal hydroxide
impregnated alumina, an alkali metal hydroxide or alkaline earth
metal hydroxide impregnated alumina combined with a clay, or an
alkali metal hydroxide or alkaline earth metal hydroxide
impregnated alumina combined with an activated carbon, as well as
any combination thereof. These processes can provide unexpectedly
efficient removal of the sulfur-containing impurities, resulting in
a higher purity, or purified, H.sub.2S stream.
[0004] In another embodiment, a process for purifying a feed stream
comprising hydrogen sulfide (H.sub.2S) and sulfur-containing
impurities is disclosed, and in this embodiment, the process can
comprise (i) contacting the feed stream with a drying agent to
remove at least a portion of moisture (H.sub.2O) from the feed
stream; and (ii) contacting the moisture (H.sub.2O) reduced feed
stream with a solid catalytic sorbent to remove at least a portion
of the sulfur-containing impurities from the feed stream to form a
purified H.sub.2S stream. Unexpectedly, the incorporation of a
drying step can increase the amount of sulfur-containing impurities
removed from the feed stream, resulting in a higher purity H.sub.2S
stream.
[0005] Additionally, processes for producing H.sub.2S are disclosed
herein. Generally, these processes can comprise (a) contacting
hydrogen and sulfur under conditions sufficient to produce a feed
stream comprising hydrogen sulfide (H.sub.2S) and sulfur-containing
impurities; and (b) contacting the feed stream with a solid
catalytic sorbent to remove at least a portion of the
sulfur-containing impurities from the feed stream to form a
purified H.sub.2S stream. Optionally, the feed stream can be
contacted with a drying agent prior to step (b) and the moisture
(H.sub.2O) reduced feed stream can be contacted with the solid
catalytic sorbent to remove at least a portion of the
sulfur-containing impurities from the feed stream to form a
purified H.sub.2S stream.
[0006] Both the foregoing summary and the following detailed
description provide examples and are explanatory only. Accordingly,
the foregoing summary and the following detailed description should
not be considered to be restrictive. Further, features or
variations can be provided in addition to those set forth herein.
For example, certain embodiments can be directed to various feature
combinations and sub-combinations described in the detailed
description.
BRIEF DESCRIPTION OF THE FIGURES
[0007] FIG. 1 presents an illustrative gas chromatograph plot
showing the respective peaks and retention times for toluene,
triphenylphosphine, triphenylphosphate, triphenylphosphine oxide,
and triphenylphosphine sulfide.
[0008] FIG. 2 presents an illustrative triphenylphosphine sulfide
calibration curve.
DEFINITIONS
[0009] To define more clearly the terms used herein, the following
definitions are provided. Unless otherwise indicated, the following
definitions are applicable to this disclosure. If a term is used in
this disclosure but is not specifically defined herein, the
definition from the IUPAC Compendium of Chemical Terminology,
2.sup.nd Ed (1997), can be applied, as long as that definition does
not conflict with any other disclosure or definition applied
herein, or render indefinite or non-enabled any claim to which that
definition can be applied. To the extent that any definition or
usage provided by any document incorporated herein by reference
conflicts with the definition or usage provided herein, the
definition or usage provided herein controls.
[0010] Herein, features of the subject matter can be described such
that, within particular aspects and/or embodiments, a combination
of different features can be envisioned. For each and every aspect,
and/or embodiment, and/or feature disclosed herein, all
combinations that do not detrimentally affect the designs,
processes, and/or methods described herein are contemplated with or
without explicit description of the particular combination.
Additionally, unless explicitly recited otherwise, any aspect,
and/or embodiment, and/or feature disclosed herein can be combined
to describe inventive features consistent with the present
disclosure.
[0011] Regarding claim transitional terms or phrases, the
transitional term "comprising," which is synonymous with
"including," "containing," "having," or "characterized by," is
open-ended and does not exclude additional, unrecited elements or
method steps. The transitional phrase "consisting of" excludes any
element, step, or ingredient not specified in the claim. The
transitional phrase "consisting essentially of" limits the scope of
a claim to the specified materials or steps and those that do not
materially affect the basic and novel characteristics of the
claimed invention. A "consisting essentially of" claim occupies a
middle ground between closed claims that are written in a
"consisting of" format and fully open claims that are drafted in a
"comprising" format. Absent an indication to the contrary,
describing a composition or method as "consisting essentially of"
is not to be construed as "comprising," but is intended to describe
the recited element that includes materials or steps which do not
significantly alter the composition or method to which the term is
applied. For example, a feedstock consisting essentially of a
material A can include impurities typically present in a
commercially produced or commercially available sample of the
recited compound or composition. When a claim includes different
features and/or feature classes (for example, a method step,
feedstock features, and/or product features, among other
possibilities), the transitional terms comprising, consisting
essentially of, and consisting of apply only to the feature class
to which it is utilized, and it is possible to have different
transitional terms or phrases utilized with different features
within a claim. For example, a method can comprise several recited
steps (and other non-recited steps), but utilize a catalytic
sorbent consisting of specific components; alternatively,
consisting essentially of specific components; or alternatively,
comprising the specific components and other non-recited
components. While compositions and methods are described in terms
of "comprising" various components or steps, the compositions and
methods can also "consist essentially of" or "consist of" the
various components or steps, unless specifically stated otherwise.
For example, a drying agent consistent with certain embodiments of
the present invention can comprise; alternatively, consist
essentially of; or alternatively, consist of a molecular sieve.
[0012] The terms "a," "an," and "the" are intended to include
plural alternatives, e.g., at least one, unless otherwise
specified. For instance, the disclosure of "a solid catalytic
sorbent" is meant to encompass one, or mixtures or combinations of
more than one, solid catalytic sorbent, unless otherwise
specified.
[0013] The terms "contact product," "contacting," and the like, are
used herein to describe compositions and methods wherein the
components are contacted together in any order, in any manner, and
for any length of time. For example, the components can be
contacted by blending or mixing. Further, unless otherwise
specified, the contacting of any component can occur in the
presence or absence of any other component of the compositions and
methods described herein. Combining additional materials or
components can be done by any suitable method. Further, the term
"contact product" includes mixtures, blends, solutions, slurries,
reaction products, and the like, or combinations thereof. Although
"contact product" can, and often does, include reaction products,
it is not required for the respective components to react with one
another. Similarly, the term "contacting" is used herein to refer
to materials which can be blended, mixed, slurried, dissolved,
reacted, treated, or otherwise contacted in some other manner.
Hence, "contacting" two or more components can result in a mixture,
a reaction product, a reaction mixture, etc.
[0014] Although any methods and materials similar or equivalent to
those described herein can be used in the practice or testing of
the invention, the typical methods and materials are herein
described.
[0015] All publications and patents mentioned herein are
incorporated herein by reference. The publications and patents
mentioned herein can be utilized for the purpose of describing and
disclosing, for example, the constructs and methodologies that are
described in the publications, which might be used in connection
with the presently described invention. The publications discussed
throughout the text are provided solely for their disclosure prior
to the filing date of the present application. Nothing herein is to
be construed as an admission that the inventors are not entitled to
antedate such disclosure by virtue of prior invention.
[0016] Applicants reserve the right to proviso out or exclude any
individual members of any such group, including any sub-ranges or
combinations of sub-ranges within the group, that can be claimed
according to a range or in any similar manner, if for any reason
Applicants choose to claim less than the full measure of the
disclosure, for example, to account for a reference that Applicants
may be unaware of at the time of the filing of the application.
Further, Applicants reserve the right to proviso out or exclude any
individual substituents, analogs, compounds, ligands, structures,
or groups thereof, or any members of a claimed group, if for any
reason Applicants choose to claim less than the full measure of the
disclosure, for example, to account for a reference that Applicants
may be unaware of at the time of the filing of the application.
DETAILED DESCRIPTION OF THE INVENTION
[0017] Disclosed herein are processes for purifying a feed stream
which can comprise hydrogen sulfide (H.sub.2S) and
sulfur-containing impurities using a solid catalytic sorbent to
form a purified H.sub.2S stream. Also disclosed herein are
processes which further employ a drying step, as well as improved
H.sub.2S production processes.
Processes for Removing Impurities from Hydrogen Sulfide Streams
[0018] Embodiments of this invention are directed to processes for
purifying feed streams comprising (or consisting essentially of, or
consisting of) hydrogen sulfide (H.sub.2S) and sulfur-containing
impurities. Herein, the terms "feed stream," "feed streams,"
"H.sub.2S feed stream," "H.sub.2S feed streams," and/or their
derivatives refer to a feed stream or feed streams comprising (or
consisting essentially of, or consisting of) hydrogen sulfide
(H.sub.2S) and sulfur-containing impurities. Such processes can
comprise (or consist essentially of, or consist of) contacting the
feed stream with a solid catalytic sorbent to remove at least a
portion of the sulfur-containing impurities from the feed stream to
form a purified H.sub.2S stream. Generally, the features of the
processes (e.g., the components and/or features of the feed stream,
the solid catalytic sorbent (e.g., material options, single or
mixed or segregated beds), the components and/or features of the
purified stream, and the process conditions under which the feed
stream and solid catalytic sorbent are contacted, among others) are
independently described herein, and these features can be combined
in any combination to further describe the disclosed purification
processes.
[0019] In some embodiments, the sulfur-containing impurities can
comprise (or consist essentially of, or consist of) elemental
sulfur, polysulfanes, or both. Polysulfanes have the general
formula, H.sub.2S.sub.n, where n.gtoreq.2, and can decompose to
form H.sub.2S and elemental sulfur. Both polysulfanes and elemental
sulfur can be detrimental in a H.sub.2S stream, for example, due to
deposits or plate-out on pipes, valve, heat exchangers,
compressors, and other process equipment.
[0020] The feed stream typically contains at least 80 wt. %
H.sub.2S, although not limited thereto. In some embodiments, for
instance, the feed stream can comprise a minimum of 80 wt. %, 82
wt. %, 85 wt. %, 88 wt. %, 90 wt. %, 95 wt. %, 98 wt. %, or 99 wt.
A H.sub.2S; additionally or alternatively, a maximum of 99.999 wt.
%, 99.99 wt. %, 99.9 wt. %, 99.8 wt. %, 99.5 wt. %, 99 wt. %, or
98.5 wt. % H.sub.2S. Generally, the weight percent of H.sub.2S that
can be present in the feed stream can be in a range from any
minimum weight percent disclosed herein to any maximum weight
percent disclosed herein. Therefore, the feed stream can contain
the following non-limiting ranges of the weight percent of
H.sub.2S: from 80 to 99.999 wt. %, from 80 to 99.99 wt. %, from 80
to 99.9 wt. %, from 90 to 99.9 wt. %, from 90 to 99.5 wt. %, from
95 to 99.999 wt. %, or from 95 to 99.9 wt. %. Other appropriate
ranges for the wt. % H.sub.2S in the feed stream are readily
apparent from this disclosure.
[0021] Although not limited thereto, sulfur-containing impurities
in the feed stream typically are a minor component of the feed
stream, often present at less than 1000-1500 ppm by weight. For
example, in some embodiments, the feed stream can comprise a
minimum of 5 ppm, 10 ppm, 15 ppm, 20 ppm, 25 ppm, 50 ppm, 75 ppm,
100 ppm, or 250 ppm (by weight) of sulfur-containing impurities;
additionally or alternatively, a maximum of 1000 ppm, 750 ppm, 500
ppm, 400 ppm, 350 ppm, 300 ppm, or 250 ppm (by weight) of
sulfur-containing impurities. Generally, the ppm by weight of
sulfur-containing impurities that can be present in the feed stream
can be in a range from any minimum ppm disclosed herein to any
maximum ppm disclosed herein. Therefore, the feed stream can
contain the following non-limiting amounts, by weight, of
sulfur-containing impurities: from 5 to 1000 ppm, from 5 to 500
ppm, from 5 to 250 ppm, from 10 to 1000 ppm, from 10 to 500 ppm,
from 10 to 250 ppm, from 10 to 100 ppm, from 25 ppm to 750 ppm, or
from 25 ppm to 250 ppm. Other appropriate ranges for the amount of
sulfur-containing impurities present in the feed stream are readily
apparent from this disclosure.
[0022] The processes disclosed herein are very effective at
removing sulfur-containing impurities from H.sub.2S-rich feed
streams. In an embodiment, the purified H.sub.2S stream can
comprise a minimum of 0.5 ppm, 1 ppm, 2 ppm, 3 ppm, 4 ppm, 5 ppm,
or 10 ppm (by weight) of sulfur-containing impurities; additionally
or alternatively, a maximum of 250 ppm, 100 ppm, 75 ppm, 50 ppm, 40
ppm, 30 ppm, or 25 ppm (by weight) of sulfur-containing impurities.
Generally, the ppm by weight of sulfur-containing impurities that
can be present in the purified H.sub.2S stream can be in a range
from any minimum ppm disclosed herein to any maximum ppm disclosed
herein. Therefore, the purified H.sub.2S stream can contain the
following non-limiting amounts, by weight, of sulfur-containing
impurities: from 0.5 to 100 ppm, from 0.5 to 50 ppm, from 0.5 to 25
ppm, from 1 to 100 ppm, from 1 to 75 ppm, from 1 to 25 ppm, from 5
to 250 ppm, from 5 ppm to 100 ppm, or from 5 ppm to 50 ppm. Other
appropriate ranges for the amount of sulfur-containing impurities
in the purified H.sub.2S stream are readily apparent from this
disclosure.
[0023] The effectiveness of the disclosed processes in removing
sulfur-containing impurities also can be quantified by determining
the percentage amount of the sulfur-containing impurities removed
from the feed stream to form the purified H.sub.2S stream (i.e.,
based on the amount of sulfur-containing impurities in the purified
H.sub.2S stream versus the amount of sulfur-containing impurities
in the feed stream). The amount of the sulfur-containing impurities
removed from the feed stream to form the purified H.sub.2S stream
can be, for example, at least 50 wt. %, at least 55 wt. %, at least
58 wt. %, at least 60 wt. %, at least 62 wt. %, at least 65 wt. %,
at least 68 wt. %, or at least 70 wt. %, based upon the total
amount of sulfur-containing impurities in the feed stream;
additionally or alternatively, a maximum of 99.99 wt. %, 99.9 wt.
%, 99 wt. %, 98.5 wt. %, 98 wt. %, 95 wt. %, or 90 wt. %, based
upon the total amount of sulfur-containing impurities in the feed
stream. Generally, the weight percent of sulfur-containing
impurities removed from the feed stream to form the purified
H.sub.2S stream can be in a range from any minimum weight percent
disclosed herein to any maximum weight percent disclosed herein.
Therefore, the amount of sulfur-containing impurities removed using
the processes disclosed herein can fall within the following
non-limiting ranges: from 50 to 99.99 wt. %, from 50 to 99.9 wt. %,
from 50 to 99 wt. %, from 60 to 99.9 wt. %, from 60 to 98 wt. %,
from 60 to 95 wt. %, or from 65 to 99 wt. %, based upon the total
amount of sulfur-containing impurities in the feed stream. Other
appropriate sulfur-containing impurity removal ranges are readily
apparent from this disclosure.
[0024] The feed stream and the solid catalytic sorbent can be
contacted at any suitable temperature, for instance, at a minimum
temperature of 0.degree. C., 5.degree. C., 10.degree. C.,
15.degree. C., or 20.degree. C.; additionally or alternatively, at
a maximum temperature of 75.degree. C., 70.degree. C., 65.degree.
C., 60.degree. C., 55.degree. C., 50.degree. C., 45.degree. C.,
40.degree. C., or 30.degree. C. Generally, the temperature at which
the feed stream and the solid catalytic sorbent can be contacted
can be in a range from any minimum temperature disclosed herein to
any maximum temperature disclosed herein. Suitable non-limiting
ranges for this contacting temperature can include the following
ranges: from 0.degree. C. to 50.degree. C., from 5.degree. C. to
45.degree. C., from 10.degree. C. to 45.degree. C., from 15.degree.
C. to 45.degree. C., from 20.degree. C. to 40.degree. C., or from
15.degree. C. to 35.degree. C. Other appropriate temperature ranges
at which the feed stream and the solid catalytic sorbent can be
contacted are readily apparent from this disclosure.
[0025] The feed stream and the solid catalytic sorbent can be
contacted at any suitable pressure, for instance, at a minimum
pressure of 34 kPa (5 psia), 70 kPa (10 psia), 103 kPa (15 psia),
173 kPa (25 psia), 345 kPa (50 psia), 517 kPa (75 psia), and 689
kPa (100 psia); additionally or alternatively, at a maximum
pressure of 3.4 MPa (500 psia), 2.8 MPa (400 psia), 2 MPa (300
psia), 1.7 MPa (250 psia), 1.3 MPa (200 psia), or 1.0 MPa (150
psia). Generally, the pressure at which the feed stream and the
solid catalytic sorbent can be contacted can be in a range from any
minimum pressure disclosed herein to any maximum pressure disclosed
herein. Suitable non-limiting ranges for the pressure at which the
feed stream and the solid catalytic sorbent can be contacted can
include the following ranges: from 34 kPa (5 psia) to 2 MPa (300
psia), from 103 kPa (15 psia) to 1.7 MPa (250 psia), from 173 kPa
(25 psia) to 1.3 MPa (200 psia), from 70 kPa (5 psia) to 1.3 MPa
(200 psia), or from 70 kPa (5 psia) to 1.0 MPa (150 psia). Other
appropriate pressure ranges at which the feed stream and the solid
catalytic sorbent can be contacted are readily apparent from this
disclosure.
[0026] Often, the process for purifying the feed stream can be a
flow process and/or a continuous process. In such circumstances,
the feed stream-solid catalytic sorbent contact time (or reaction
time) can be expressed in terms of weight hourly space velocity
(WHSV)--the ratio of the weight of feed stream which comes in
contact with a unit weight of solid catalytic sorbent per unit time
(units of g/g/hr). In some embodiments, the process can be
conducted at minimum WHSV of 0.05, 0.1, 0.25, 0.5, 0.75, or 1;
additionally or alternatively, a maximum value of 5, 4, 3, 2.5, or
2. Generally, the WHSV can be in a range from any minimum WHSV
disclosed herein to any maximum WHSV disclosed herein. Suitable
WHSV ranges can include, but are not limited to, from 0.05 to 5;
alternatively, from 0.05 to 4; alternatively, from 0.1 to 5;
alternatively, from 0.1 to 4; alternatively, from 0.1 to 3;
alternatively, from 0.1 to 2; alternatively, from 0.2 to 2;
alternatively, from 0.2 to 1; alternatively, from 0.5 to 5;
alternatively, from 0.4 to 2.5; alternatively, from 0.5 to 2.5;
alternatively, from 0.8 to 3; or alternatively, from 1 to 3. Other
appropriate WHSV ranges are readily apparent from this
disclosure.
[0027] Any suitable reactor or vessel can be used to purify the
feed stream, non-limiting examples of which can include a flow
reactor, a continuous reactor, a fixed bed reactor, and a stirred
tank reactor, including more than one reactor in series or in
parallel, and including any combination of reactor types and
arrangements. In particular embodiments consistent with this
invention, the feed stream can contact a fixed bed of the solid
catalytic sorbent in a suitable vessel, e.g., in a continuous fixed
bed reactor. In further embodiments, combinations of more than one
solid catalytic sorbent can be used, such as a mixed bed of a first
catalytic sorbent and a second catalytic sorbent, or sequential
beds of a first catalytic sorbent and a second catalytic sorbent.
In these and other embodiments, the feed stream can flow upward or
downward through the fixed bed. For instance, the feed stream can
contact the first catalytic sorbent and then the second catalytic
sorbent in a downward flow orientation, and the reverse in an
upward flow orientation.
[0028] In some embodiments of this invention, the purification
process can further comprise a step of contacting the feed stream
with a drying agent to remove at least a portion of any moisture
(H.sub.2O) present in the feed stream, prior to and/or concurrently
with contacting the feed stream with the solid catalytic sorbent.
Hence, a process to purify a feed stream comprising hydrogen
sulfide (H.sub.2S) and sulfur-containing impurities can comprise
(i) contacting the feed stream with a drying agent to remove at
least a portion of moisture (H.sub.2O) from the feed stream; and
(ii) contacting the moisture (H.sub.2O) reduced feed stream with a
solid catalytic sorbent to remove at least a portion of the
sulfur-containing impurities from the feed stream to form a
purified H.sub.2S stream. This process encompasses circumstances
where step (i) and step (ii) are conducted concurrently, such as in
a mixed bed of a drying agent and a solid catalytic sorbent. The
drying agent can be in the same vessel as the solid catalytic
sorbent (e.g., sequential beds and/or mixed beds), or the drying
step can be conducted in a vessel upstream of the vessel containing
the catalytic sorbent.
[0029] Wet or moisture-containing feed streams, prior to contacting
the drying agent, often can comprise a minimum of 0.00001 wt. %,
0.0001 wt. %, 0.001 wt. %, 0.002 wt. %, 0.005 wt. %, 0.01 wt. %,
0.1 wt. %, 1 wt. %, 2 wt. %, or 5 wt. % H.sub.2O; additionally or
alternatively, a maximum of 15 wt. %, 10 wt. %, 5 wt. %, 2 wt. %, 1
wt. %, or 0.1 wt. % H.sub.2O. Generally, the weight percent of
H.sub.2O that can be present in the feed stream can be in a range
from any minimum weight percent disclosed herein to any maximum
weight percent disclosed herein. Therefore, the feed stream can
contain the following non-limiting ranges of the weight percent of
H.sub.2O: from 0.00001 to 15 wt. %, from 0.005 to 15 wt. %, from
0.05 to 10 wt. %, from 0.001 to 10 wt. %, from 0.1 to 5 wt. %, from
1 to 15 wt. %, from 0.001 to 1 wt. %, or from 2 to 12 wt. %. Other
appropriate ranges for the weight percent H.sub.2O in the feed
stream are readily apparent from this disclosure.
[0030] The drying step can be very effective at removing
moisture/H.sub.2O from the H.sub.2S feed stream. In some
embodiments, the feed stream, after contacting the drying agent,
can comprise a minimum of 0.1 ppm, 0.5 ppm, 1 ppm, 2 ppm, 5 ppm, 10
ppm, or 25 ppm (by weight) of H.sub.2O; additionally or
alternatively, a maximum of 1000 ppm, 500 ppm, 200 ppm, 100 ppm, 50
ppm, 10 ppm, or 5 ppm (by weight) of H.sub.2O. Generally, the ppm
by weight of H.sub.2O that can be present in the feed stream, after
contacting the drying agent, can be in a range from any minimum ppm
disclosed herein to any maximum ppm disclosed herein. Therefore,
the amount of H.sub.2O in the feed stream, after contacting the
drying agent, can contain the following non-limiting amounts, by
weight, of H.sub.2O: from 0.1 to 500 ppm, from 0.1 to 250 ppm, from
0.1 to 10 ppm, from 1 to 500 ppm, from 1 to 100 ppm, from 1 to 50
ppm, from 5 to 250 ppm, from 5 ppm to 100 ppm, or from 5 ppm to 50
ppm. Other appropriate ranges for the weight percent H.sub.2O in
the feed stream after contact with the drying agent are readily
apparent from this disclosure.
[0031] In the processes described herein, any suitable drying agent
can be utilized. In some embodiments, the drying agent can comprise
(or consist essentially of, or consist of) calcium chloride,
calcium sulfate, magnesium sulfate, alumina, silica, or a molecular
sieve, as well as any combination thereof; alternatively, calcium
chloride; alternatively, calcium sulfate; alternatively, magnesium
sulfate; alternatively, alumina; alternatively, silica; or
alternatively, a molecular sieve. One or more than one drying agent
can be used in various embodiments of this invention. In one
embodiment, for example, the drying agent can comprise (or consist
essentially of, or consist of) calcium sulfate; alternatively, a
molecular sieve; alternatively, a 3 A molecular sieve; or
alternatively, a UOP Type 3 A molecular sieve.
[0032] Unexpectedly, the processes disclosed herein can be
conducted for relatively long periods of time with significant
percentages of the sulfur-containing impurities being removed from
the feed stream to form the purified H.sub.2S stream. For example,
processes consistent with the present invention can remove at least
45 wt. % (or at least 50 wt. %, or at least 55 wt. %, or at least
60 wt. %, or any percentage amount disclosed herein) of the
sulfur-containing impurities for a time period of at least 5 hours,
at least 10 hours, at least 24 hours, at least 48 hours, at least
100 hours, at least 200 hours, at least 250 hours, at least 300
hours, at least 400 hours, and so forth. In some embodiments, the
amount of sulfur-containing impurities removed can be at least 45
wt. % (or at least 50 wt. %, or at least 55 wt. %, or at least 60
wt. %, or any percentage amount disclosed herein) for a maximum
time period of 10000 hours, 7500 hours, 5000 hours, 2000 hours,
1500 hours, 1000 hours, 750 hours, 500 hours, or 250 hours.
Generally, a minimum percentage amount of the sulfur-containing
impurities can be removed over a time period ranging from any
minimum time period to any maximum time period disclosed herein. In
some non-limiting embodiments, the length of the time period, in
which a specific minimum amount of the sulfur-containing impurities
is removed from the feed stream, can be in a range from 5 to 10000
hours, 5 to 1000 hours, from 5 to 750 hours, from 5 to 500 hours,
from 5 to 50 hours, from 24 to 1000 hours, from 24 to 250 hours,
from 100 to 1000 hours, from 100 to 750 hours, or from 250 to 1500
hours. Other ranges of time periods are readily apparent from this
disclosure. As an example, these long periods of time with
significant percentages of the sulfur-containing impurities being
removed can be achieved in a flow or continuous process, such as,
for example, in a continuous fixed bed reactor.
Solid Catalytic Sorbents
[0033] Embodiments of this invention are directed to processes for
purifying a feed stream comprising H.sub.2S and sulfur-containing
impurities (e.g., elemental sulfur, polysulfanes). Such processes
can comprise contacting the feed stream with a solid catalytic
sorbent to remove at least a portion of the sulfur-containing
impurities from the feed stream to form a purified H.sub.2S stream.
Solid catalytic sorbents contemplated herein can encompass a
variety of specific materials, and these materials, while not
wishing to be bound by theory, can absorb elemental sulfur, or can
catalytically decompose polysulfanes (e.g., to form H.sub.2S and
elemental sulfur), or can absorb elemental sulfur and catalytically
decompose polysulfanes, or can operate by some other mechanism.
Regardless of the manner in which the materials described herein
operate, they are collectively referred to as solid catalytic
sorbents.
[0034] In an embodiment, the solid catalytic sorbent can comprise a
clay, an alkali metal hydroxide or alkaline earth metal hydroxide
impregnated activated carbon, an alkali metal hydroxide or alkaline
earth metal hydroxide impregnated alumina, an alkali metal
hydroxide or alkaline earth metal hydroxide impregnated alumina
combined with a clay, or an alkali metal hydroxide or alkaline
earth metal hydroxide impregnated alumina combined with an
activated carbon, as well as any combination thereof. Hence,
combinations (e.g., a mixed bed, sequential beds) of different
solid catalytic sorbents can be employed. Within the present
application and claims, alkali metal hydroxide or alkaline earth
metal hydroxide impregnated refers to all methods of introducing an
alkali metal hydroxide or alkaline earth metal hydroxide into the
material (e.g., contacting or treating the material with an alkali
metal hydroxide or alkaline earth metal hydroxide, among other
methods).
[0035] As utilized herein, the terms "alkali metal hydroxide or
alkaline earth metal hydroxide impregnated," its subforms (e.g.,
"alkali metal hydroxide impregnated," or "alkaline earth metal
hydroxide impregnated"), and/or derivatives, refer to all forms of
a clay, alumina, and/or carbon that has been treated with an alkali
metal hydroxide or alkaline earth metal hydroxide. As such, the
terms "alkali metal hydroxide or alkaline earth metal hydroxide
impregnated," its subforms (e.g., "alkali metal hydroxide
impregnated," or "alkaline earth metal hydroxide impregnated"),
and/or derivatives, refer to clays, aluminas, or activated carbons
having alkali metal hydroxide, alkaline earth metal hydroxide,
alkali metal oxide, and/or alkaline earth metal oxide present in
the material.
[0036] In some embodiments, the solid catalytic sorbent can
comprise a clay, such as, for instance, a Filtrol.RTM. clay, an
Oil-Dri.RTM. clay, an alkali metal hydroxide or alkaline earth
metal hydroxide impregnated clay, as well as combinations thereof.
In one embodiment, the clay can comprise a Filtrol.RTM. clay, while
in another embodiment, the clay can comprise an Oil-Dri.RTM. clay.
Yet, in another embodiment, the clay can comprise an alkali metal
hydroxide or alkaline earth metal hydroxide impregnated clay. Any
suitable base or caustic material can be used to prepare the alkali
metal hydroxide or alkaline earth metal hydroxide impregnated clay,
non-limiting examples of which can include sodium hydroxide,
potassium hydroxide, and the like, as well as mixtures thereof.
While not being limited thereto, the alkali metal hydroxide or
alkaline earth metal hydroxide impregnated clay, activated carbon,
and/or alumina can be prepared by mixing a clay, activated carbon,
and/or alumina with an alkali metal hydroxide and/or alkaline earth
metal hydroxide solution, allowing sufficient time for impregnation
of the clay, activated carbon, and/or alumina, and then filtering,
drying, and/or calcining the impregnated clay, activated carbon,
and/or alumina.
[0037] In one embodiment, the solid catalytic sorbent can comprise
an alkali metal hydroxide or alkaline earth metal hydroxide
impregnated activated carbon, while in another embodiment, the
solid catalytic sorbent can comprise an alkali metal hydroxide or
alkaline earth metal hydroxide impregnated alumina. In some
embodiments, the alkali metal hydroxide or alkaline earth metal
hydroxide used to produce the impregnated material can comprise an
alkali metal hydroxide. The alkali metal hydroxide can comprise
lithium hydroxide, sodium hydroxide, potassium hydroxide, or a
combination thereof; alternatively, lithium hydroxide;
alternatively, sodium hydroxide; or alternatively, potassium
hydroxide. In other embodiments, the alkali metal hydroxide or
alkaline earth metal hydroxide used to produce the impregnated
material can comprise an alkaline earth metal hydroxide. The
alkaline earth metal hydroxide can comprise magnesium hydroxide,
calcium hydroxide, strontium hydroxide, barium hydroxide, or a
combination thereof; alternatively, magnesium hydroxide;
alternatively, calcium hydroxide; alternatively, strontium
hydroxide; or alternatively, barium hydroxide.
[0038] In certain embodiments, the alkali metal hydroxide or
alkaline earth metal hydroxide impregnated activated carbon can be
a sodium hydroxide and/or potassium hydroxide impregnated activated
carbon. An illustrative example of a commercially-available alkali
metal hydroxide or alkaline earth metal hydroxide impregnated
activated carbon suitable for use as a solid catalytic sorbent as
described herein is Calgon.RTM. Carbon ST1-X.
[0039] In certain embodiments, the alkali metal hydroxide or
alkaline earth metal hydroxide impregnated alumina can be a sodium
hydroxide and/or potassium hydroxide impregnated alumina. An
illustrative example of a commercially-available alkali metal
hydroxide or alkaline earth metal hydroxide impregnated alumina
suitable for use as a solid catalytic sorbent as described herein
is Selexsorb.RTM. COS.
[0040] While not limited thereto, solid catalytic sorbents suitable
for use herein can have a surface area of at least 10 m.sup.2/g, 20
m.sup.2/g, 25 m.sup.2/g, 40 m.sup.2/g, 50 m.sup.2/g, 75 m.sup.2/g,
or 100 m.sup.2/g; additionally or alternatively, the solid
catalytic sorbent can have a maximum surface area of 1000
m.sup.2/g, 500 m.sup.2/g, 400 m.sup.2/g, 300 m.sup.2/g, 250
m.sup.2/g, 200 m.sup.2/g, or 150 m.sup.2/g. Generally, the surface
area of the solid catalytic sorbent can be in a range from any
minimum surface area disclosed herein to any maximum surface
disclosed herein. Suitable non-limiting ranges for the surface area
can include the following ranges: from 10 m.sup.2/g to 500
m.sup.2/g, from 25 m.sup.2/g to 250 m.sup.2/g, from 50 m.sup.2/g to
200 m.sup.2/g, from 20 m.sup.2/g to 400 m.sup.2/g, or from 40
m.sup.2/g to 300 m.sup.2/g. Other appropriate ranges for the
surface area of the solid catalytic sorbents are readily apparent
from this disclosure.
[0041] The particle size (e.g., average particle size) of the solid
catalytic sorbent generally is not limited to any particular range.
The appropriate particle size can be determined based on the design
of the vessel/reactor in which the purification process is
conducted, the feed stream flow rate, and pressure drop
limitations, amongst other considerations. In some embodiments,
pellets or granules of the catalytic sorbent can be used, while in
other embodiments, particulates having average particle sizes in
the 5 mesh to 100 mesh range can be used; alternatively, in the 5
mesh to 50 mesh range; alternatively, in the 7 mesh to 40 mesh
range; or alternatively, in the 8 mesh to 35 mesh range. Other
appropriate ranges for the particle size of the solid catalytic
sorbents are readily apparent from this disclosure.
[0042] Combinations of more than one solid catalytic sorbent can be
used in the disclosed processes for purifying feed streams
comprising H.sub.2S and sulfur-containing impurities. In one
embodiment, for example, the solid catalytic sorbent can comprise
an alkali metal hydroxide or alkaline earth metal hydroxide
impregnated alumina combined with a clay. In another embodiment,
the solid catalytic sorbent can comprise an alkali metal hydroxide
or alkaline earth metal hydroxide impregnated alumina combined with
an activated carbon. In another embodiment, the solid catalytic
sorbent can comprise an alkali metal hydroxide or alkaline earth
metal impregnated hydroxide alumina combined with an alkali metal
hydroxide or alkaline earth metal hydroxide impregnated activated
carbon. In yet another embodiment, the solid catalytic sorbent can
comprise a clay in combination with an activated carbon. In still
another embodiment, the solid catalytic sorbent can comprise a clay
in combination with an alkali metal hydroxide or alkaline earth
metal hydroxide impregnated activated carbon.
[0043] As described herein, combinations of more than one solid
catalytic sorbent can be used in the disclosed processes for
purifying feed streams comprising H.sub.2S and sulfur-containing
impurities. For instance, the combination of the solid catalytic
sorbents can comprise a mixed bed of the individual solid catalytic
sorbents. Alternatively, the combination of the solid catalytic
sorbents can comprise sequential beds of the individual solid
catalytic sorbents, such as in one vessel or in two or more
sequential separate vessels.
Hydrogen Sulfide Production Processes
[0044] Also encompassed herein are various processes for producing
H.sub.2S. One such H.sub.2S production process can comprise (or
consist essentially of, or consist of) (a) contacting hydrogen and
sulfur under conditions sufficient to produce a feed stream
comprising hydrogen sulfide and sulfur-containing impurities; and
(b) contacting the feed stream with a solid catalytic sorbent to
remove at least a portion of the sulfur-containing impurities from
the feed stream to form a purified H.sub.2S stream. In a further
embodiment, the feed stream can be contacted with a drying agent
prior to and/or concurrently with step (b), if desired. Generally,
the features of the H.sub.2S production processes (e.g., the
components and/or features of the step to produce H.sub.2S, the
components and/or features of the feed stream, the solid catalytic
sorbent (e.g., material options, single or mixed or segregated
beds), the components and/or features of the purified stream, and
the process conditions under which the feed stream and solid
catalytic sorbent are contacted, among others) are independently
described herein, and these features can be combined in any
combination to further describe the disclosed H.sub.2S production
processes. Moreover, other process steps can be conducted before,
during, and/or after any of the steps listed in the disclosed
processes, unless stated otherwise.
[0045] The purification step (b) and optional drying step are
discussed herein. Any embodiments and features of the purification
step and/or the drying step described herein can be utilized in the
processes for producing H.sub.2S and, accordingly, are encompassed
herein.
[0046] In step (a), hydrogen and sulfur are contacted under
conditions sufficient to produce a feed stream comprising hydrogen
sulfide (H.sub.2S) and sulfur-containing impurities. Any suitable
method known to those of skill in the art for reacting hydrogen and
sulfur (e.g., hydrogen gas and molten sulfur) to produce H.sub.2S
can be utilized. Hydrogen and sulfur can be contacted and reacted
under non-catalytic conditions, or a catalyst can be used. Suitable
catalysts, temperatures, pressures, and reactant ratios are known
to those of skill in the art and are described, for example, in
U.S. Pat. Nos. 7,833,509 and 7,887,777.
[0047] In an embodiment, the H.sub.2S production process can be an
in situ process, for example, steps (a)-(b) can be performed in the
same reactor system. However, in an alternative embodiment, the
purification step (b) can be conducted external to the reactor
system utilized to produce the H.sub.2S feed stream, such as in
another vessel and/or location. In additional embodiments, there
can be a cooling step of any stream using methods and means known
to those of skill in the art (e.g., all or a portion of the feed
stream can be cooled in a heat exchanger after step (a), and then
returned to the feed stream and/or processed through the
purification steps/equipment).
Examples
[0048] The invention is further illustrated by the following
examples, which are not to be construed in any way as imposing
limitations to the scope of this invention. Various other aspects,
embodiments, modifications, and equivalents thereof which, after
reading the description herein, can suggest themselves to one of
ordinary skill in the art without departing from the spirit of the
present invention or the scope of the appended claims.
[0049] The purification experiments were conducted utilizing a
fixed bed apparatus. The apparatus was configured such that the
H.sub.2S feed stream was fed from a vessel in a liquid state
through a flow meter/controller. Once the H.sub.2S feed stream
passed through the flow meter/controller, it was passed through a
back pressure regulator, where the pressure was reduced to the
desired value. The H.sub.2S feed stream was then passed through a
three-way valve to either a sample/holding tank or the solid
catalytic sorbent bed (or a drier bed and the solid catalytic
sorbent bed) and then to a sample/holding tank. The solid catalytic
sorbent bed (34.5'' in length and 1/2'' in diameter) was packed
with 50 to 100 mL of the desired solid catalytic sorbent. The drier
bed, when utilized, was 34.5'' in length and 1/2'' in diameter, and
was packed with approximately 90 mL of the desired drying
agent.
[0050] Sulfur impurity testing samples were obtained by passing the
H.sub.2S feed stream, either untreated or purified, though the
sample/holding tank for a predetermined amount of time to ensure
that a representative sample was taken. The H.sub.2S feed stream
flow was then directed to a sulfur impurity testing vessel
containing a known amount of triphenylphosphine (TPP) solution. The
H.sub.2S feed stream flow rate and time to the sulfur impurity
testing vessel was monitored and recorded so that the total mass of
H.sub.2S feed stream charged to the sulfur impurity testing vessel
could be determined.
[0051] The amounts of elemental sulfur and polysulfanes in the
hydrogen sulfide feed stream were determined by contacting a known
amount of liquid H.sub.2S feed stream sample with a toluene
solution of triphenylphosphine (TPP) in a pressurized vessel where
the elemental sulfur and/or polysulfanes reacted with
triphenylphosphine to form triphenylphosphine sulfide. The pressure
was released from pressurized vessel and H.sub.2S removed from the
toluene solution. The toluene solution was then analyzed using gas
chromatography and the amount of triphenylphosphine sulfide found
in the remaining toluene solution was compared against a
calibration curve to determine the amount of elemental sulfur
and/or polysulfanes in the hydrogen sulfide. An internal standard,
triphenylphosphate was utilized to minimize variability between
analyses. This method was found to provide reliable results down to
low ppm concentrations of elemental sulfur and/or polysulfanes in
H.sub.2S, with an accuracy within .+-.2 ppm and a precision from
analysis to analysis of .+-.1 ppm. The chemicals used were:
TABLE-US-00001 Purity Reagent CAS No. (%) Comments
Triphenylphosphine 603-35-0 99.0 Protect from air to minimize (TPP)
oxidation to triphenylphosphine oxide Triphenylphosphine 3878-45-3
99.0 Sulfide (TPPS) Triphenylphosphate 115-86-6 99.0 (TPPo.sub.4)
Toluene, Reagent 108-88-3 99.5 Purge with N.sub.2 or argon to Grade
minimize oxygen and store to prevent oxygen build up
[0052] Equipment used in this analytical method included volumetric
flasks (500 mL and 50 mL), volumetric pipets (1 mL), gas
chromatographic sample vials (1-10 mL), and gas chromatographic
syringes (1-10 .mu.L) capable of delivering a consistent 1 .mu.L
sample (either manually or automatically) into a GC. The GC used
was capable of ramp heating from ambient temperature to 300.degree.
C., equipped with a heated split injector inlet, a 30 m HP-5 column
(30 m.times.0.32 mm.times.0.25 .mu.m film thickness) or equivalent,
and a flame ionization detector (FID).
[0053] The testing vessel was a 250 mL to 1 L pressure vessel
equipped with a means of receiving a liquid hydrogen sulfide sample
(and maintaining the hydrogen sulfide in a liquid state), a
stirrer, a sample port for sample retrieval, a means of
heating/cooling the vessel to maintain room temperature (25.degree.
C.), a rupture disc or other pressure relief device rated for at
least 800 psig at 22.degree. C., a means to safely vent hydrogen
sulfide (preferably to a flare system), a means to pass an inert
gas (e.g. nitrogen) into the pressure vessel to pressurize the
vessel to a desired pressure and/or to purge hydrogen sulfide from
the analysis solution before sampling, and a drain (or other means)
to remove analysis solution from the pressure vessel and to clean
and dry the pressure vessel after use.
[0054] For calibration curve sample preparation, 1.95 g of
triphenylphosphate and 250 mL of reagent grade toluene were added
to a clean and dry 500 mL volumetric flask. The volumetric flask
was then swirled to dissolve the triphenylphosphate. Calibration
standard solutions, 10, were then prepared containing
triphenylphosphine sulfide, triphenylphosphine, and
triphenylphosphate having approximately the same phosphorus molar
content. Each calibration standard solution was prepared by
charging 1 mL of the triphenylphosphate stock solution, the
appropriate amounts of triphenylphosphine and triphenylphosphine
sulfide to prepare calibration standards having a
triphenylphosphine sulfide to triphenylphosphate mass ratios
covering a range from approximately 0.2 to approximately 360, and
25 mL of reagent grade toluene to clean, dry 50 mL volumetric
flask. The 50 mL volumetric flask was then swirled to dissolve the
TPP and TPPS. The 50 mL volumetric flask was then filled to the 50
mL line with reagent grade toluene. The contents of the 50 mL
volumetric flask were then mixed to form the calibration standard
solution. The mass of triphenylphosphine sulfide,
triphenylphosphine, and triphenylphosphate for each calibration
standard solution was recorded and the triphenylphosphine sulfide
to triphenylphosphate mass ratio and triphenylphosphine to
triphenylphosphine mass ratio was calculated for each calibration
standard solution. Table A below provides data for the preparation
of one representative set of calibration standard solutions.
TABLE-US-00002 TABLE A GC calibration standards and GC experimental
data 1 2 3 4 5 Internal Standard Preparation Data and Mass Ratios
TPPO.sub.4 (g) 0.0040 0.0040 0.0040 0.0040 0.0040 TPPS (g) 1.4248
0.7171 0.1413 0.1053 0.0708 TPP (g) 0.0006 0.6371 1.1442 1.1835
1.2078 TPP mass % 0.02 48.27 88.90 91.44 93.38 TPPS mass % 99.32
50.95 10.24 7.34 5.30 TPPS/TPPO.sub.4 mass ratio 356.200 179.275
35.325 26.325 17.700 TPP/TPPO.sub.4 mass ratio 0.150 159.275
286.050 295.875 301.950 Gas Chromatographic Analysis Area Counts
and Ratios TPP area count 392.1 721448.0 1347386.5 1796891.8
1609634.7 TPPO.sub.4 area count 5146.71 4329.50 4618.22 5686.23
5108.28 TPPO.sub.4 mass % 0.30 0.29 0.30 0.29 0.30 TPPS area count
1692734.4 758424.52 155235.13 143926.38 91418.92 TPP/TPPO.sub.4
area count 0.076 166.635 291.754 316.007 315.103 ratio
TPPS/TPPO.sub.4 area count 328.897 175.176 33.614 25.311 17.896
ratio 6 7 8 9 10 Internal Standard Preparation Data and Mass Ratios
TPPO.sub.4 (g) 0.0040 0.0040 0.0040 0.0040 0.0040 TPPS (g) 0.0427
0.0132 0.0072 0.0014 0.0003 TPP (g) 1.2349 1.2594 1.26540 1.2710
1.2722 TPP mass % 95.13 97.13 96.72 97.75 96.61 TPPS mass % 3.27
1.04 0.69 0.17 0.12 TPPS/TPPO.sub.4 mass ratio 10.675 3.300 1.800
0.350 0.200 TPP/TPPO.sub.4 mass ratio 308.725 314.850 316.350
317.750 318.050 Gas Chromatographic Analysis Area Counts and Ratios
TPP area count 1353715.3 1706007.8 1532490.2 1750961.2 1532951.2
TPPO.sub.4 area count 3951.53 5243.84 4688.74 5352.18 4576.36
TPPO.sub.4 mass % 0.28 0.30 0.30 0.30 0.29 TPPS area count 46482.72
18298.07 10789.71 2974.74 1935.53 TPP/TPPO.sub.4 area count 342.580
325.335 326.845 327.149 334.972 ratio TPPS/TPPO.sub.4 area count
11.763 3.489 2.301 0.556 0.423 ratio
[0055] Sample analysis, calibration standard solution analyses, and
test solution analyses, were performed by injecting a 1 .mu.L
sample of the appropriate sample unto the gas chromatographic
system equipped as described herein, using the following gas
chromatographic analysis conditions:
[0056] 1. Injector Conditions [0057] Sample Inlet
Temperature--275.degree. C. [0058] Helium flow rate--Constant Flow
at 2.0 mL/min [0059] Split Ratio--1:1
[0060] 2. Oven Temperature Program [0061] Initial
Temperature--120.degree. C. [0062] Initial Time--0 minutes [0063]
Temperature Ramp--15.degree. C./min to 300.degree. C. [0064] Final
Temperature--300.degree. C. [0065] Final Time--20 minutes
[0066] 3. Detector Conditions [0067] Flame Ionization Detector
(FID) Temperature--325.degree. C. [0068] H.sub.2 Flow
rate--Constant Flow at 10 mL/min [0069] Air Flow rate--Constant
Flow at 150 mL/min
[0070] Calibration curves were prepared as follows. The total area
count and the individual area count for triphenylphosphine,
triphenylphosphate, and triphenylphosphine sulfide were measured
for each gas chromatographic analysis and recorded. The
triphenylphosphine sulfide to triphenylphosphate area count ratio
and the triphenylphosphine to triphenylphosphine area count ratio
from the gas chromatographic analysis of the calibration standard
solutions were determined and recorded. FIG. 1 provides a
representative gas chromatograph providing the associated peaks and
retention times for toluene, triphenylphosphine,
triphenylphosphate, triphenylphosphine oxide, and
triphenylphosphine sulfide. Table A provides the individual area
counts for triphenylphosphine, triphenylphosphate, and
triphenylphosphine sulfide, and the triphenylphosphine sulfide to
triphenylphosphate area count ratio and triphenylphosphine to
triphenylphosphine area count ratio for a single gas
chromatographic analysis of each calibration standard solution.
[0071] Each calibration standard solution was measured 3 times and
the average result of the three analyses was used to construct a
triphenylphosphine sulfide calibration curve. The
triphenylphosphine sulfide calibration curve was constructed by
plotting the triphenylphosphine sulfide/triphenylphosphate mass
ratio vs. the triphenylphosphine sulfide/triphenylphosphate area
count ratio. Generally, the plot of triphenylphosphine
sulfide/triphenylphosphate mass ratio vs. the triphenylphosphine
sulfide/triphenylphosphate area count ratio was fit to a linear
equation with a high R.sup.2 value (greater than 0.99). FIG. 2
illustrates a sample triphenylphosphine sulfide calibration
curve.
[0072] The elemental sulfur and/or polysulfane content analysis of
the hydrogen sulfide samples had these steps. [0073] A. Prepare a
triphenylphosphine/triphenylphosphate stock solution having a
triphenylphosphine concentration of approximately 0.025 g/mL and a
triphenylphosphate concentration of approximately 0.04 g/mL in
reagent grade toluene. [0074] B. Contact the
triphenylphosphine/triphenylphosphate stock solution with a known
amount of liquid H.sub.2S sample having from 1.times.10.sup.-4
grams to 1.5.times.10.sup.-1 grams of elemental sulfur and/or
polysulfanes and react the elemental sulfur and/or polysulfanes
with the triphenylphosphine in the
triphenylphosphine/triphenylphosphate stock solution to form
triphenylphosphine sulfide. Preferably the liquid hydrogen sulfide
sample should be contacted with the
triphenylphosphine/triphenylphosphate stock solution in an amount
such that half of the triphenylphosphine in the
triphenylphosphine/triphenylphosphate remains after reacting the
elemental sulfur and/or polysulfanes in the liquid hydrogen sulfide
sample with the triphenylphosphine in the
triphenylphosphine/triphenylphosphate stock solution to ensure that
there is an adequate amount of triphenylphosphine to react with the
elemental sulfur and/or polysulfanes. Vent hydrogen sulfide from
the test sample. [0075] C. Perform a gas chromatographic analysis
on the remaining toluene solution and use the calibration curve to
determine the amount of triphenylphosphine sulfide in the toluene
solution. [0076] D. Calculate the amount of elemental sulfur and/or
polysulfanes (as ppm by weight, or ppmw, sulfur) using the amount
of liquid hydrogen sulfide contacted with the
triphenylphosphine/triphenylphosphate stock solution.
[0077] If the elemental sulfur and/or polysulfane content of the
hydrogen sulfide is not known, preliminary hydrogen sulfide sample
analyses may need to be performed to determine the appropriate
hydrogen sulfide charge quantity and/or
triphenylphosphine/triphenylphosphate stock solution charge
quantity to obtain a triphenylphosphine sulfide to
triphenylphosphate area count ratio falling well within the range
of the calibration curve.
[0078] A triphenylphosphate stock solution was prepared by charging
a clean, dry 50 mL volumetric flask with 1.95 grams of
triphenylphosphate and 25 mL of reagent grade toluene. The 50 mL
volumetric flask was then swirled to dissolve the
triphenylphosphate. Once the triphenylphosphate dissolved, the 50
mL volumetric flask was filled to the line with reagent grade
toluene and then thoroughly mixed to from the triphenylphosphate
stock solution. The concentration of the triphenylphosphate stock
solution was then calculated and recorded (0.039 g/mL
triphenylphosphate).
[0079] A triphenylphosphine/triphenylphosphate stock solution was
prepared by charging a clean dry 500 mL volumetric flask with 12.72
g of triphenylphosphine. Using a volumetric pipet, a 1 mL portion
of the previously prepared triphenylphosphate stock solution was
transferred to the 500 mL volumetric flask by volumetric pipet. The
500 mL volumetric flask was then charged with 250 mL of reagent
grade toluene and swirled to dissolve the triphenylphosphine. Once
the triphenylphosphine dissolved, the 500 mL volumetric flask was
filled to the line with reagent grade toluene and then thoroughly
mixed to from the triphenylphosphine/triphenylphosphate stock
solution. The concentration of the
triphenylphosphine/triphenylphosphate stock solution was then
calculated and recorded (0.02544 g/mL triphenylphosphine,
7.80.times.10.sup.-5 g/mL triphenylphosphate).
[0080] All operations handling triphenylphosphine and/or solutions
containing triphenylphosphine were performed to minimize contact
with air to minimize triphenylphosphine oxide formation. The
triphenylphosphine/triphenylphosphate stock solution often can be
stored for up to 6 months in a refrigerator if the stock solution
is sealed well and protected from air.
[0081] Testing for sulfur-containing impurities was performed as
follows. Using a volumetric pipet, 50 mL of the previously prepared
triphenylphosphine/triphenylphosphate stock solution was charged to
a clean, appropriately sized testing vessel (e.g., 1 L autoclave),
equipped as described herein. The testing vessel was sealed, then
pressurized to 500 psig with nitrogen, and checked to ensure that
it was free of leaks. The nitrogen pressure was then released so
that the testing vessel pressure returned to atmospheric pressure.
Stirring of the triphenylphosphine/triphenylphosphate stock
solution was then initiated and the
triphenylphosphine/triphenylphosphate stock solution brought to a
temperature of 25.degree. C. Next, a liquid hydrogen sulfide sample
(ranging from 25 to 156 grams) was charged to the testing vessel
over a period of 5 to 10 minutes, and the amount charged was
recorded. The testing vessel was then sealed and additional
nitrogen pressure was added (if necessary) to ensure that the
hydrogen sulfide was in a liquid state. The hydrogen sulfide and
triphenylphosphine/triphenylphosphate stock solution mixture was
then stirred and maintained at 25.degree. C. for 30 minutes.
[0082] Upon completion of the 30 minute reaction period, hydrogen
sulfide was vented from the testing vessel. The testing vessel was
then swept with dry nitrogen for approximately 30 minutes as an
additional precaution to purge hydrogen sulfide from the testing
vessel. The testing vessel was then pressured to 30 psig with
nitrogen, the hydrogen sulfide test solution removed from the
reactor, and a gas chromatographic sample of the hydrogen sulfide
test solution collected in a small gas chromatogram test vial.
[0083] A 1 .mu.L sample of the hydrogen sulfide test solution was
injected into the GC using the method described herein. The total
area count and the individual area count for triphenylphosphine,
triphenylphosphate, and triphenylphosphine sulfide were measured
from the gas chromatographic analysis and recorded. The
triphenylphosphine sulfide to triphenylphosphate area count ratio
and triphenylphosphine to triphenylphosphine area count ratio from
the gas chromatographic analysis of the hydrogen sulfide test
solution were determined and recorded. The hydrogen sulfide test
solution was analyzed three times and the average
triphenylphosphine sulfide to triphenylphosphate area count ratio
and triphenylphosphine to triphenylphosphine area count ratio
determined for the hydrogen sulfide test solution.
[0084] The amount of sulfur-containing impurities (e.g., elemental
sulfur and/or polysulfanes) in the hydrogen sulfide sample was then
calculated using the gas chromatographic calibration curve, the
amount of the triphenylphosphine/triphenylphosphate stock solution
used for the hydrogen sulfide test, the concentration of
triphenylphosphate in the triphenylphosphine/triphenylphosphate
stock solution, and the quantity of hydrogen sulfide used in the
hydrogen sulfide test. First, the amount of triphenylphosphine in
the hydrogen sulfide test solution was determined utilizing the
calibration curve. Then utilizing the calibration curve in FIG. 2,
the mass of triphenylphosphine was calculated using the
equation:
TPPS (g)={[TPP/TPPO.sub.4 stock solution volume
(mL).times.TPPO.sub.4 concentration TPP/TPPO.sub.4 stock solution
(g/mL)].times.[1.0747.times.(Hydrogen Sulfide test solution
TPPS/TPPO4 area count ratio)-1.308]}.
In this equation, TPPS is triphenylphosphine sulfide, TPP is
triphenylphosphine, TPPO.sub.4 is triphenylphosphate, 1.0747 is the
slope of the linear fit of the calibration curve in FIG. 2, and
1.308 is the y-intercept of linear fit of the calibration curve in
FIG. 2.
[0085] The amount of sulfur-containing impurities (e.g., elemental
sulfur and/or polysulfanes) in the hydrogen sulfide test sample was
then calculated using the equation:
Sulfur impurities (ppmw)={[(TPPS (g)/294.35 g/mol).times.32.06
g/mol]/H.sub.2S sample mass (g)}.times.10.sup.6.
In this equation, 294.35 g/mol is the molecular weight of TPPS,
32.06 g/mol is the molecular weight of sulfur, and 10.sup.6
converts the results to ppmw.
[0086] The accuracy of this analytical method was validated by
contacting a test solution having a known amount of sulfur
dissolved in THF. A THF test solution having approximately 25 ppmw
elemental sulfur was prepared, and contacted with a
triphenylphosphine/triphenylphosphate test solution, under a
nitrogen atmosphere with stirring, at 25.degree. C. for 30 minutes.
The reacted solution was analyzed by gas chromatography, and the
amount of elemental sulfur was calculated using the calibration
curve and appropriate equations. Using this method, two independent
tests provided results of 24.8 ppmw and 25.6 ppmw for the THF
solution containing 25 ppmw sulfur.
HYDROGEN SULFIDE PURIFICATION EXAMPLES 1-41
[0087] Table I summarizes certain solid catalytic sorbent materials
that were evaluated, and their description and respective average
particle size. Table II summarizes the solid catalytic sorbent
materials used in Examples 1-7, the operating conditions, and the
effectiveness of the respective solid catalytic sorbent materials
in removing sulfur-containing impurities from a H.sub.2S feed
stream. The clay solid catalytic sorbent A (Oil-Dri.RTM. clay)
removed about 30-35 wt. % of the impurities from the H.sub.2S feed
stream. The performance of the carbon based solid catalytic
sorbents (J--coal sourced carbon from Calgon.RTM. Carbon, D--Coal
Source Carbon from Cabot Norit, and E--Coconut Source Carbon)
ranged from <30 wt. % of impurities removed up to 57 wt. %. The
solid catalytic sorbents H (styrene-divinylbenzene) and F (3 A
molecular sieves) were relatively ineffective in removing the
impurities from the H.sub.2S feed stream. Table II indicates that
none of the solid catalytic sorbents tested in Examples 1-7 removed
more than 60 wt. % of the sulfur-containing impurities from the
H.sub.2S stream.
[0088] Table III summarizes the solid catalytic sorbent materials
used in Examples 8-11, the operating conditions, and the
effectiveness of the respective solid catalytic sorbent materials
in removing sulfur-containing impurities from a H.sub.2S feed
stream. Solid catalyst sorbent K (alkali metal hydroxide
impregnated activated carbon) was prepared from solid catalytic
sorbent D (activated carbon) by dissolving 75 g of 98-99% NaOH
pellets in 75.4 g of deionized water, and mixing this solution with
70 g of solid catalytic sorbent D in a beaker, soaking the carbon
for 1 hr, filtering through #41 ashless paper using a vacuum flask,
and then drying in an oven for 12 hr at 115.degree. C. Solid
catalytic sorbent K contained 18.2 wt. % Na. Solid catalytic
sorbent L (alkali metal hydroxide impregnated clay) was prepared
from solid catalytic sorbent A by dissolving 4 g of 98-99% NaOH
pellets in 100 g of deionized water, mixing the solution with 100 g
of solid catalytic sorbent A in a beaker, soaking the clay for 1
hr, filtering through #41 ashless paper using a vacuum flask, and
then drying in an oven for 12 hr at 115.degree. C.
[0089] In Table III, the H.sub.2S feed stream flow orientation was
upward through the fixed bed for Example 8, and downward for
Examples 9-11. Table III indicates that all of solid catalytic
sorbents in Examples 8-11 were able to remove over 60 wt. % of the
sulfur-containing impurities from the H.sub.2S stream. By comparing
Examples 8-9 to Examples 1-2 and 6, it was determined that the
alkali metal hydroxide impregnation of clay or carbon unexpectedly
increased the amount of impurities removed by 30-40 wt. %. Similar
performance was also unexpectedly achieved using solid catalytic
sorbent G (alkali metal hydroxide impregnated alumina): 73 wt. % of
the sulfur-containing impurities from the H.sub.2S feed stream were
removed.
[0090] Table IV summarizes the solid catalytic sorbent materials
used in Examples 12-19, the operating conditions, and the
effectiveness of the respective sorbent combinations in removing
sulfur-containing impurities from a H.sub.2S feed stream. Examples
12-14 used a mixed bed of solid catalytic sorbents G (1/3 by
volume) and D (2/3 by volume), and the H.sub.2S feed stream flow
orientation was downward. Examples 15 and 17 used a segregated bed
of solid catalytic sorbents G (1/3 by volume) and D (2/3 by
volume), and the H.sub.2S feed stream flow orientation was
downward. Example 16 used a segregated bed of solid catalytic
sorbents G (1/3 by volume) and D (2/3 by volume), and the H.sub.2S
feed stream flow orientation was upward. Example 18 used a
segregated bed of solid catalytic sorbents G (1/2 by volume) and D
(1/2 by volume), and the H.sub.2S feed stream flow orientation was
upward. Example 19 used a segregated bed of solid catalytic
sorbents G (1/3 by volume) and A (2/3 by volume), and the H.sub.2S
feed stream flow orientation was upward.
[0091] Table IV indicates that the addition of alkali metal
hydroxide impregnated alumina to either carbon or clay in a mixed
or segregated bed resulted in unexpected increases in the amount of
impurities removed by 20-50 wt. % over the carbon or clay materials
alone (see Examples 12-19 versus Examples 1-2 and 6).
[0092] Table V summarizes the solid catalytic sorbent materials
used in Examples 20-24, the operating conditions, and the
effectiveness of the respective sorbent materials and combinations
in removing sulfur-containing impurities from a H.sub.2S feed
stream. In examples 20-21, a dryer bed containing either sorbent F
(molecular sieve drying agent) or sorbent I (calcium sulfate drying
agent), operating at 1 WHSV and 25.degree. C. was used. At these
conditions, and with about 50 ppm of moisture entering in the
incoming H.sub.2S feed, the moisture content leaving the dryer bed
and entering the fixed bed (downward flow) was about 1 ppm.
[0093] Examples 20-21 in Table V indicate that the use of sorbent F
or sorbent I alone was not effective at removing impurities from a
H.sub.2S feed stream. Example 22 shows the amount of impurities
removed from the H.sub.2S feed stream when a drying agent is not
used prior to the solid catalytic sorbent fixed bed. As shown by
Examples 23-24, the use of a drying agent prior to the solid
catalytic sorbent fixed bed resulted in an unexpected increase in
the amount of impurities removed by 7-10 wt. %.
[0094] Table VI summarizes the operating conditions and
effectiveness of solid catalytic sorbent B (alkali metal hydroxide
impregnated carbon) in removing sulfur-containing impurities from a
H.sub.2S feed stream over a long duration of time (Examples 25-30).
Upstream of the sorbent bed was a dryer using sorbent F (molecular
sieve drying agent), which was replaced with fresh sorbent at 654
hr. Surprisingly, Table VI indicates that solid catalytic sorbent
B, in conjunction with drying the H.sub.2S feed stream, was
effective at removing 60-70 wt. % of the sulfur-containing
impurities from a H.sub.2S feed stream for a time period of over
650 hr at a WHSV of 1.
[0095] Table VII summarizes the solid catalytic sorbent materials
used in Examples 31-41, the operating conditions, and the
effectiveness of the respective solid catalytic sorbent materials
or combinations in removing sulfur-containing impurities from a
H.sub.2S feed stream. Examples 31-33 and 39-41 used a mixed bed of
solid catalytic sorbents G (1/3 by volume) and D (2/3 by volume),
while Example 34 used a segregated bed of solid catalytic sorbents
G (1/2 by volume) and D (1/2 by volume). Examples 31-34 indicate
that the removal of impurities from a H.sub.2S feed was improved at
lower operating pressures (e.g., less than 250 psig, less than 200
psig, less than 150 psig, less than 50 psig). Examples 35-38
indicate that the removal of impurities from a H.sub.2S feed was
improved at lower operating temperatures (e.g., around 25.degree.
C.). Examples 39-41 indicate that the removal of impurities from a
H.sub.2S feed was improved at WHSV's of about 1.
TABLE-US-00003 TABLE I Summary of Materials A-J Sorbent Designation
Material Description Particle Size A Oil-Dri .RTM. Clay, Bentonite
(Oil-Dri of America) 20-25 mesh B ST1-X Carbon, KOH .ltoreq.10 wt.
% (Calgon .RTM. Carbon) 4 mm pellet C IVP Carbon, NaOH .ltoreq.20%
wt. % (Calgon .RTM. Carbon) 3.6 mm granule D Darco 4X12 Coal Source
Carbon (Cabot Norit) 12-40 mesh E 4X8 60CTC Coconut Source Carbon
(Carbon Activated 4.75 .times. 2.36 mm Corporation) F 3A Molecular
Sieves, Aluminosilicate (UOP) 8-12 mesh G Selexsorb .RTM. COS,
Sodium/Alkali Treated Alumina (Alcoa 7-14 mesh Industrial
Chemicals) H Lewatit MP 64 styrene-divinylbenzene, dimethylamino
groups 0.3-1.0 mm free base form (Bayer AG) I Calcium Sulfate
(Aldrich) 325 mesh J CAL 12X40 Coal Source Carbon (Calgon .RTM.
Carbon) 12-40 mesh K NaOH treated Darco 4X12 Coal Source
Carbon(Cabot Norit) -- L NaOH treated Oil-Dri .RTM. Clay --
TABLE-US-00004 TABLE II Examples 1-7 H.sub.2S Initial Final Sorbent
Sorbent Flow Impurity Impurity % % weight volume WHSV Rate Temp
Pressure Conc. Conc. Impurities Impurities Example Sorbent (g) (mL)
(g/g/hr) (g/hr) (.degree. C.) (psig) (ppm) (ppm) Removed Remaining
1 A 38.8 57 1.5 58 25 40.3 91.9 60.9 34 66 2 A 38.8 57 1.5 58 25
42.7 91.9 64.6 30 70 3 H 38.8 58 1.5 58 25 50.2 30.5 30.8 0 100 4 F
47.0 57 1.5 60 25 41.2 42.4 32.4 24 76 5 J 24.7 86 1.0 25 25 50.0
32.8 14.2 57 43 6 D 40.5 86 0.5 20 50 301.7 56.5 45.2 20 80 7 E
41.1 86 1.0 41 30 348.5 101.5 74.3 27 73
TABLE-US-00005 TABLE III Examples 8-11 H.sub.2S Initial Final
Sorbent Sorbent Flow Impurity Impurity % % weight volume WHSV Rate
Temp Pressure Conc. Conc. Impurities Impurities Example Sorbent (g)
(mL) (g/g/hr) (g/hr) (.degree. C.) (psig) (ppm) (ppm) Removed
Remaining 8 K 40.1 67 1.5 60 25 38.4 42.4 16.6 61 39 9 L 38.3 57
1.5 58 25 48.4 91.9 27.7 70 30 10 C 37.0 86 1.0 37 25 50.0 17.8 6.4
64 36 11 G 37.7 44 1.5 56 25 49.1 30.5 8.1 73 27
TABLE-US-00006 TABLE IV Examples 12-19 H.sub.2S Initial Final
Sorbent Sorbent Flow Impurity Impurity % % weight volume WHSV Rate
Temp Pressure Conc. Conc. Impurities Impurities Example Sorbent (g)
(mL) (g/g/hr) (g/hr) (.degree. C.) (psig) (ppm) (ppm) Removed
Remaining 12 G + D 51.1 86 1.5 77 25 123.1 74.6 41.0 45 55 13 G + D
51.1 86 0.5 25 25 121.3 74.6 39.3 47 53 14 G + D 51.1 86 1.0 51 25
117.7 74.6 25.2 66 34 15 G/D 50.4 86 1.5 75 25 50.2 30.5 15.3 50 50
16 G/D 50.4 86 1.0 50 25 43.2 30.5 13.1 57 43 17 G/D 50.4 86 1.5 75
25 41.6 30.5 10.2 67 33 18 G/D 32.9 57 1.5 49 25 45.6 30.5 10.1 67
33 19 G/A 42.1 57 1.5 58 25 51.9 91.9 30.8 66 34
TABLE-US-00007 TABLE V Examples 20-24 H.sub.2S Initial Final
Sorbent Sorbent Flow Impurity Impurity % % weight volume WHSV Rate
Temp Pressure Conc. Conc. Impurities Impurities Example Sorbent (g)
(mL) (g/g/hr) (g/hr) (.degree. C.) (psig) (ppm) (ppm) Removed
Remaining 20 F 47.0 57 1.5 60 25 41.2 42.4 32.4 24 76 21 I 36.3 86
1.0 36 25 50.0 65.1 62.6 4 96 22 B 37.0 86 1.0 37 25 50.0 17.8 6.7
62 38 23 F/B 36.3 86 1.0 36 25 50.0 65.1 20.2 69 31 24 I/B 36.3 86
1.0 36 25 50.0 65.1 18.0 72 28
TABLE-US-00008 TABLE VI Examples 25-30 H.sub.2S Initial Final
Sorbent Sorbent Flow Impurity Impurity % % Time weight volume WHSV
Rate Temp Pressure Conc. Conc. Impurities Impurities Example (hr)
(g) (mL) (g/g/hr) (g/hr) (.degree. C.) (psig) (ppm) (ppm) Removed
Remaining 25 7 36.3 86 1.0 36 25 50.0 56.9 20.4 64 36 26 104 36.3
86 1.0 36 25 50.0 35.1 11.0 69 31 27 209 36.3 86 1.0 36 25 50.0
65.1 17.5 72 27 28 287 36.3 86 1.0 36 25 50.0 65.1 19.1 71 29 29
654 36.3 86 1.0 36 25 50.0 65.1 24.6 62 38 30 720 36.3 86 1.0 36 25
50.0 65.1 30.7 53 47
TABLE-US-00009 TABLE VII Examples 31-41 H.sub.2S Initial Final
Sorbent Sorbent Flow Impurity Impurity % weight volume WHSV Rate
Temp Pressure Conc. Conc. Flow Impurities Example Sorbent (g) (mL)
(g/g/hr) (g/hr) (.degree. C.) (psig) (ppm) (ppm) Orientation
Remaining 31 G + D 51.1 86 1.0 51 25 349.8 101.5 86.1 Down 84 32 G
+ D 51.1 86 1.0 51 25 138.2 74.6 28.7 Down 39 33 G + D 51.1 86 1.0
51 25 117.7 74.6 25.2 Down 34 34 G/D 32.9 57 1.0 33 25 40.2 30.5
0.2 Up 1 35 K 40.1 67 1.5 60 25 38.4 42.4 16.6 Up 39 36 K 40.1 67
1.5 60 35 44.7 42.4 25.2 Up 59 37 D 40.5 86 0.5 20 50 301.7 56.5
57.7 Down 100 38 D 41.2 86 0.5 21 25 343.0 101.5 88.7 Down 87 39 G
+ D 50.4 86 1.5 75 25 50.2 30.5 15.3 Down 50 40 G + D 50.4 86 1.0
50 25 43.2 30.5 13.1 Down 43 41 G + D 50.4 86 0.5 25 25 41.3 30.5
15.8 Down 52
[0096] The invention is described above with reference to numerous
aspects and embodiments, and specific examples. Many variations
will suggest themselves to those skilled in the art in light of the
above detailed description. All such obvious variations are within
the full intended scope of the appended claims. Other embodiments
of the invention can include, but are not limited to, the following
(embodiments typically are described as "comprising" but,
alternatively, can "consist essentially of" or "consist of" unless
specifically stated otherwise):
Embodiment 1
[0097] A process to purify a feed stream comprising hydrogen
sulfide (H.sub.2S) and sulfur-containing impurities (e.g.,
elemental sulfur, polysulfanes), the process comprising:
[0098] contacting the feed stream with a solid catalytic sorbent to
remove at least a portion of the sulfur-containing impurities from
the feed stream to form a purified H.sub.2S stream;
[0099] wherein the solid catalytic sorbent comprises a clay; an
alkali metal hydroxide or alkaline earth metal hydroxide
impregnated activated carbon; an alkali metal hydroxide or alkaline
earth metal hydroxide impregnated alumina; an alkali metal
hydroxide or alkaline earth metal hydroxide impregnated alumina
combined with a clay; an alkali metal hydroxide or alkaline earth
metal hydroxide impregnated alumina combined with an activated
carbon; or any combination thereof.
Embodiment 2
[0100] The process defined in embodiment 1, wherein the solid
catalytic sorbent comprises the clay.
Embodiment 3
[0101] The process defined in embodiment 2, wherein the clay
comprises a Filtrol Clay.RTM., an Oil-Dri.RTM. clay, an alkali
metal hydroxide or alkaline earth metal hydroxide impregnated clay,
or a combination thereof.
Embodiment 4
[0102] The process defined in embodiment 2, wherein the clay
comprises a Filtrol.RTM. clay.
Embodiment 5
[0103] The process defined in embodiment 2, wherein the clay
comprises an Oil-Dri.RTM. clay.
Embodiment 6
[0104] The process defined in embodiment 1, wherein the solid
catalytic sorbent comprises the alkali metal hydroxide or alkaline
earth metal hydroxide impregnated activated carbon.
Embodiment 7
[0105] The process defined in embodiment 1, wherein the solid
catalytic sorbent comprises the alkali metal hydroxide or alkaline
earth metal hydroxide impregnated alumina.
Embodiment 8
[0106] The process defined in embodiment 1, wherein the solid
catalytic sorbent comprises the alkali metal hydroxide or alkaline
earth metal hydroxide impregnated alumina combined with the
clay.
Embodiment 9
[0107] The process defined in embodiment 1, wherein the solid
catalytic sorbent comprises the alkali metal hydroxide or alkaline
earth metal hydroxide impregnated alumina combined with the
activated carbon.
Embodiment 10
[0108] The process defined in any of embodiments 1 or 6-9, wherein
the alkali metal hydroxide or alkaline earth metal hydroxide
comprises an alkali metal hydroxide.
Embodiment 11
[0109] The process defined in any of embodiments 1 or 6-10, wherein
the alkali metal hydroxide comprises lithium hydroxide, sodium
hydroxide, potassium hydroxide, or a combination thereof.
Embodiment 12
[0110] The process defined in any of embodiments 1 or 6-10, wherein
the alkali metal hydroxide comprises sodium hydroxide.
Embodiment 13
[0111] The process defined in any of embodiments 1 or 6-10, wherein
the alkali metal hydroxide comprises potassium hydroxide.
Embodiment 14
[0112] The process defined in any of embodiments 1 or 6-9, wherein
the alkali metal hydroxide or alkaline earth metal hydroxide
comprises an alkaline earth metal hydroxide.
Embodiment 15
[0113] The process defined any of embodiments 1, 6-9, or 14,
wherein the alkaline earth metal hydroxide comprises magnesium
hydroxide, calcium hydroxide, strontium hydroxide, barium
hydroxide, or a combination thereof.
Embodiment 16
[0114] The process defined in any of embodiments 1, 6-9, or 14,
wherein the alkaline earth metal hydroxide comprises magnesium
hydroxide.
Embodiment 17
[0115] The process defined in any of embodiments 1, 6-9, or 14,
wherein the alkaline earth metal hydroxide comprises calcium
hydroxide.
Embodiment 18
[0116] The process defined in any of embodiments 1 or 6, wherein
the alkali metal hydroxide or alkaline earth metal hydroxide
impregnated activated carbon is a sodium hydroxide and/or potassium
hydroxide impregnated activated carbon.
Embodiment 19
[0117] The process defined in embodiment any of embodiments 1 or 6,
wherein the alkali metal hydroxide or alkaline earth metal
hydroxide impregnated activated carbon is Calgon.RTM. Carbon
ST1-X.
Embodiment 20
[0118] The process defined in any of embodiments 1 or 7-9, wherein
the alkali metal hydroxide or alkaline earth metal hydroxide
impregnated alumina is a sodium hydroxide and/or potassium
hydroxide impregnated alumina.
Embodiment 21
[0119] The process defined in any of embodiments 1 or 7-9, wherein
the alkali metal hydroxide or alkaline earth metal hydroxide
impregnated alumina is Selexsorb.RTM. COS.
Embodiment 22
[0120] The process defined in any of embodiments 1-21, wherein the
feed stream contacts a fixed bed of the solid catalytic sorbent in
a vessel.
Embodiment 23
[0121] The process defined in embodiment 22, wherein a combination
of solid catalytic sorbents comprises a mixed bed of the solid
catalytic sorbents.
Embodiment 24
[0122] The process defined in embodiment 22, wherein a combination
of solid catalytic sorbents comprises sequential beds of the solid
catalytic sorbents.
Embodiment 25
[0123] The process defined in any of embodiments 1-24, wherein the
feed stream comprises any wt. % of H.sub.2S disclosed herein, e.g.,
at least 80 wt. %, at least 90 wt. %, from 80 wt. % to 99.999 wt.
%, from 90 wt. % to 99.9 wt. %, etc.
Embodiment 26
[0124] The process defined in any of embodiments 1-25, wherein the
feed stream comprises any minimum amount of sulfur-containing
impurities disclosed herein, e.g. a minimum of 5 ppm, a minimum of
10 ppm, a minimum of 25 ppm (by weight), etc.
Embodiment 27
[0125] The process defined in any of embodiments 1-26, wherein the
feed stream comprises an amount of sulfur-containing impurities in
any range disclosed herein, e.g., from 5 to 500 ppm, from 10 to 500
ppm, from 10 to 250 ppm, from 25 to 250 ppm (by weight), etc.
Embodiment 28
[0126] The process defined in any of embodiments 1-27, wherein the
purified H.sub.2S stream comprises an amount of sulfur-containing
impurities in any range disclosed herein, e.g. a maximum of 100
ppm, a maximum of 75 ppm, in a range from 0.5 to 100 ppm, in a
range from 1 to 75 ppm (by weight), etc.
Embodiment 29
[0127] The process defined in any of embodiments 1-28, wherein any
percentage amount disclosed herein of the sulfur-containing
impurities are removed from the feed stream to form the purified
H.sub.2S stream, e.g., at least 50 wt. %, at least 60 wt. %, from
50 to 99.9 wt. %, from 60 to 99.9 wt. %, etc.
Embodiment 30
[0128] The process defined in any of embodiments 1-29, wherein the
feed stream and the solid catalytic sorbent are contacted at a
temperature in any range disclosed herein, e.g., from 0.degree. C.
to 50.degree. C., from 5.degree. C. to 45.degree. C., from
15.degree. C. to 35.degree. C., etc.
Embodiment 31
[0129] The process defined in any of embodiments 1-30, wherein the
feed stream and the solid catalytic sorbent are contacted at a
pressure in any range disclosed herein, e.g., from 34 kPa (5 psia)
to 2 MPa (300 psia), from 103 kPa (15 psia) to 1.7 MPa (250 psia),
from 173 kPa (25 psia) to 1.3 MPa (200 psia), from 70 kPa (5 psia)
to 1.0 MPa (150 psia), etc.
Embodiment 32
[0130] The process defined in any of embodiments 1-31, wherein the
feed stream and the solid catalytic sorbent are contacted at a WHSV
in any range disclosed herein, e.g., from 0.1 to 5, from 0.2 to 2,
from 0.4 to 2.5, etc.
Embodiment 33
[0131] The process defined in any of embodiments 1-32, wherein the
solid catalytic sorbent has a surface area in any range disclosed
herein, from 10 m.sup.2/g to 500 m.sup.2/g, from 25 m.sup.2/g to
250 m.sup.2/g, from 50 m.sup.2/g to 200 m.sup.2/g, etc.
Embodiment 34
[0132] The process defined in any of embodiments 1-33, wherein the
solid catalytic sorbent has any particle configuration (e.g.,
granule, pellet, particulate, etc.) and/or is in any average
particle size range disclosed herein, e.g., from 5 mesh to 50 mesh,
from 7 mesh to 40 mesh, from 8 mesh to 35 mesh, etc.
Embodiment 35
[0133] The process defined in any of embodiments 1-34, wherein the
process further comprises a step of contacting the feed stream with
a drying agent to remove at least a portion of moisture (H.sub.2O)
from the feed stream prior to contacting the feed stream with the
solid catalytic sorbent.
Embodiment 36
[0134] The process defined in embodiment 35, wherein the drying
agent comprises calcium chloride, calcium sulfate, magnesium
sulfate, alumina, silica, a molecular sieve, or any combination
thereof.
Embodiment 37
[0135] The process defined in embodiment 35, wherein the drying
agent comprises any suitable molecular sieve, e.g., a UOP Type 3 A
molecular sieve, etc.
Embodiment 38
[0136] The process defined in any of embodiments 35-37, wherein the
feed stream, prior to contacting the drying agent, comprises an
amount of H.sub.2O in any range disclosed herein, e.g., a minimum
of 0.00001 wt. %, a minimum of 0.001 wt. %, a minimum of 2 wt. %,
from 0.00001 to 15 wt. %, from 0.005 to 10 wt. %, from 1 to 8 wt.
%, from 0.1 to 5 wt. %, etc.
Embodiment 39
[0137] The process defined in any of embodiments 35-38, wherein the
feed stream, after contacting the drying agent, comprises an amount
of H.sub.2O in any range disclosed herein, e.g., a maximum of 500
ppm, a maximum of 10 ppm, from 0.1 to 500 ppm, from 0.1 to 10 ppm
H.sub.2O (by weight), etc.
Embodiment 40
[0138] The process defined in any of embodiments 1-39, wherein any
minimum disclosed percentage amounts of the sulfur-containing
impurities are removed from the feed stream to form the purified
H.sub.2S stream over a time period in any range of time periods
disclosed herein, e.g., at least 5 hours, at least 24 hours, at
least 250 hours, from 5 to 10000 hours, from 5 to 1000 hours, from
24 to 500 hours, from 100 to 750 hours, etc.
Embodiment 41
[0139] A H.sub.2S production process comprising:
[0140] (a) contacting hydrogen and sulfur under conditions
sufficient to produce a feed stream comprising hydrogen sulfide
(H.sub.2S) and sulfur-containing impurities; and
[0141] (b) purifying the feed stream by the process defined in any
of embodiments 1-40.
* * * * *